Method and apparatus for wound treatment

ABSTRACT

A wound treatment device comprises a polyurethane or polyether foam pad, adapted for insertion substantially within a wound cavity; a pump for supplying fluid flow to the wound site; and a collection canister for receiving wound fluids drawn from the wound cavity. The foam pad, pump and collection canister are in fluid communication with one another through a single hospital grade hose having a plurality of tiny apertures in the portion that is central to the foam pad. These apertures are adapted to allow fluids from the wound cavity to be drawn into the flow from the pump to the canister according to Bernoulli&#39;s theorem.

RELATED APPLICATIONS

[0001] This application is a continuation of U.S. Pat. No. 6,767,334 tobe granted Jul. 27, 2004 which is a continuation of InternationalApplication No. PCT/US99/30702 entitled METHOD AND APPARATUS FOR WOUNDTREATMENT filed Dec. 23, 1999, now abandoned, which claimed priority toU.S. Provisional Patent Application Ser. No. 60/113,732 entitled METHODAND APPARATUS FOR WOUND TREATMENT filed Dec. 23, 1998. By thisreference, the full disclosures, including the drawings, of U.S.provisional patent application Ser. No. 60/113,732 and InternationalApplication No. PCT/US99/30702 are incorporated herein.

TECHNICAL FIELD

[0002] The present invention relates to the treatment of wounds. Moreparticularly, the invention relates to the therapeutic application of apositive fluid flow to a wound site for the promotion of wound healing.

BACKGROUND ART

[0003] It is known in the prior art that wound closure requires that theepithelial and subcutaneous tissues adjacent the wound migrate towardthe wound. Unfortunately, in the case of large or infected wounds, oftenthe result of chronic disease or pressure sores, spontaneous closuredoes not take place. In these cases, localized swelling forms near thesurface of the wound restricting flow of blood. As a result of thisdiminished blood flow the wound is unable to successfully fightbacterial infection. The resulting increased infection causes furtherrestriction of blood flow, which in turn results in further diminishedblood flow and so forth, ultimately leading to the necessity for radicalintervention. In many cases the patient requires hospitalization fordrug administration and/or surgical treatment.

[0004] The application of continuous negative pressure has been shown tocontribute significantly to wound closure. Such applications typicallyinvolve the insertion of an open cell foam pad into a wound region. Thepad is then covered with a polymer sheet to seal the region fromatmosphere. Thereafter, negative pressure is applied to the wound sitethrough a tube having one end inserted into the interior of the foam padand the opposite end attached to a vacuum pump via an interposed chamberfor collection of wound fluids. Clinical results demonstrate that suchapplications of negative pressure promote the migration of epithelialand subcutaneous tissue toward the wound while serving to evacuate woundexudates and reduce bacterial density.

[0005] Unfortunately, the application of continuous negative pressuremakes difficult the administration of topical disinfectant drugs andcontrol of the local atmospheric content and does little to promotedrying of the wound area. It is therefore desired to achieve infectioncontrol in a manner that promotes the application of topicaldisinfectants while allowing the caregiver to adjust the localatmospheric condition, including content and temperature. The removal ofwound fluids through continuous negative pressure also suffers thedisadvantage of requiring strict infection control. This is most oftenaccomplished through the provision of very expensive hydrophobic filtersbetween the collection canister and vacuum pump and other safetymeasures. It is therefore desirable to eliminate the necessity for suchexpensive apparatuses while still providing a safe and effective meansfor the removal of wound exudates.

[0006] In accordance with the foregoing objects, the present invention—amethod and apparatus for wound treatment—generally comprises apolyurethane or polyether foam pad, adapted for insertion substantiallywithin a wound cavity; a pump for supplying fluid flow to the woundsite; and a collection canister for receiving wound fluids drawn fromthe wound cavity. The foam pad, pump and collection canister are influid communication with one another through a single hospital gradehose having a plurality of tiny apertures in the portion that is centralto the foam pad. These apertures are adapted to allow fluids from thewound cavity to be drawn into the flow from the pump to the canisteraccording to Bernoulli's theorem, which states generally that the workdone on a fluid is equal to the change in kinetic energy of the fluid.

[0007] Many other features, objects and advantages of the presentinvention will be apparent to those of ordinary skill in the relevantarts, especially in light of the foregoing discussions and the followingdrawings, exemplary detailed description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Although the scope of the present invention is much broader thanany particular embodiment, a detailed description of the preferredembodiment follows together with illustrative figures, wherein likereference numerals refer to like components, and wherein:

[0009]FIG. 1 shows a partial cross section of a known apparatus forapplication of continuous negative pressure to a wound site; and

[0010]FIG. 2 shows a partial cross section of a preferred embodiment ofthe present invention as applied to a wound site, including in blockdiagram the pump and collection canister forming a part thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0011] Although those of ordinary skill in the art will readilyrecognize many alternative embodiments, especially in light of theillustrations provided herein, this detailed description is exemplary ofthe preferred embodiment of the present invention, the scope of which islimited only by the claims that may be drawn hereto.

[0012] Referring to FIG. 1, there is shown a partial cross-sectionalview of an open cell polyurethane or polyether foam pad 10 as insertedinto a wound site 11 for application of continuous negative pressure aspreviously known in the art. As detailed in the figure, the foam pad 10is cut top size so as to pack the foam 10 into the wound cavity 12,making contact with the full surface 13 of the cavity 12. A drainagetube 14, preferably comprising medical grade polyvinyl chloride (PVC),is terminated within the central portion 15 of the foam pad 10 and thepad 10 and tube 14 combination is covered with a surgical drape 16. Thedrape 16 is preferably adhered firmly to the intact skin 17 peripheralthe wound site 11 as well as to the drainage tube 14 in order to providean airtight seal around the wound 11. Negative pressure is then appliedthrough the drainage tube 14 utilizing known apparatus not shown here.

[0013] Referring now to FIG. 2, there is shown a partial cross-sectionalview of an open cell-polyurethane or polyether foam pad 10 as insertedinto a wound site 11 for application of positive pressure according tothe teachings of the present invention. While the present inventionemploys many principles known from the art of negative pressureapplications for wound site preparation, material selection, and eventherapeutic modality, the present invention varies from the known art inseveral critical areas. First, the present invention is adapted to applya positive pressure to the wound site 11. As shown in the figure, thePVC tube 18 providing fluid communication both to and from the insertedpad 10 comprises a plurality of tiny apertures 19 in the region 15central to the pad 10. Positive pressure, preferably generated with anon-oil type clean air delivery pump 20 meeting applicable hospitalstandards such as UL-544, is delivered to a first end 21 of the tube. Byvarying the temperature and flow rate of the fluid delivered to thewound site 11 through the tube 18 and provided apertures 19, thecaregiver is given the ability to control the drying characteristics ofthe fluid. Additionally, the caregiver can vary the content of the fluidin order to promote increased healing. For example, the pump 20 may beadapted to deliver pure 02 for a localized hyperbaric effect or 03 forozone treatment and infection controlling drugs may be easily admittedinto the flow stream for topical administration to the wound 11.

[0014] In addition, the placement of the tiny apertures 19 in the flowstream relative to the second, or drainage, end 22 of the tube 18creates a venturi. As is generally known in the relevant arts, a venturioperates through the Bernoulli effect to create a relative low pressurein areas of increased fluid flow rate in a closed or semi-closed system.According to the present invention, the drainage end 22 of the tube 18is connected to fluid collection canister 23 wherein the local pressureis controlled to ensure establishment of the desired venturi. In thismanner, a localized suction is created at the wound site 11,notwithstanding the fact that the pressure at the wound 11 will begreater than that of the surrounding atmosphere, whereby wound exudatesmay be safely drawn from the wound 11. This helps to eliminate moisturebuildup at the wound site 11 and reduces bacterial density, therebyaiding in the control of infection and assisting in the control ofedema.

[0015] As an additional benefit, the system of the present inventioneliminates the need for many of the more expensive elements of infectioncontrol. For example, because the collection canister 23 is at theterminal end of the pressure delivery apparatus, the requirements forhydrophobic filtering and strict contamination monitoring are reduced oreliminated. This makes the apparatus of the present invention availableat far more economical rates, while maintaining patient safety standardsintact.

[0016] While the foregoing description is exemplary of the preferredembodiment of the present invention, those of ordinary skill in therelevant arts will recognize the many variations, alterations,modifications, substitutions and the like as are readily possible,especially in light of this description and the accompanying drawingsand claims drawn hereto. In any case, because the scope of the presentinvention is much broader than any particular embodiment, the foregoingdetailed description should not be construed as a limitation of thescope of the present invention, which is limited only by the claims thatmay be drawn hereto.

What is claimed is:
 1. An apparatus for the promotion of wound closure,said apparatus comprising: a pad adapted for insertion substantiallywithin a wound cavity; a source of fluid flow; a reservoir adapted forcollection of wound fluids; and a fluid conduit adapted for conveyingsaid fluid flow from said source, through said pad and to saidreservoir, said fluid conduit being further adapted to draw wound fluidsfrom adjacent said pad into said fluid flow and away from the woundcavity.
 2. The apparatus as recited in claim 1, wherein said adaptationto draw wound fluids comprises an implementation of Bernoulli's theorem.3. The apparatus as recited in claim 1, wherein said fluid conduitcomprises a hose.
 4. The apparatus as recited in claim 2, wherein saidimplementation comprises the provision of a plurality of apertures insaid fluid conduit, said apertures being enveloped within said pad. 5.The apparatus as recited in claim 1, wherein said fluid source isadapted for the introduction to said fluid flow of a pharmaceuticalproduct.
 6. The apparatus as recited in claim 1, wherein said fluidsource is adapted for the influence, through said fluid conduit, of theatmospheric condition in the region of the wound cavity.
 7. Theapparatus as recited in claim 6, wherein said influence compriseseffecting atmospheric content.
 8. The apparatus as recited in claim 6,wherein said influence comprises effecting temperature.
 9. The apparatusas recited in claim 7, wherein said influence further compriseseffecting temperature.
 10. The apparatus as recited in claim 1, whereinsaid reservoir comprises a canister.
 11. A method for the promotion ofwound closure, said method comprising the steps of: inserting a padsubstantially within a wound cavity; providing a source of fluid flow;providing a reservoir adapted for collection of wound fluids; andconveying said fluid flow through a fluid conduit from said source,through said pad and to said reservoir, said fluid conduit being adaptedto draw wound fluids from adjacent said pad into said fluid flow andaway from the wound cavity.